In recent years, organic EL displays using an organic electroluminescence device as an alternative to liquid crystal displays have become a focus of attention. The organic EL displays are of a self-luminous type, so it is considered that the organic EL displays have advantages of a wide viewing angle, low power consumption and adequate response to high-definition high-speed video signals. Therefore, the organic EL displays have been developed to achieve the practical use thereof.
FIG. 6 shows a configuration of the organic electroluminescence device. The organic electroluminescence device comprises an anode 112, an organic layer 115 including a hole injection layer 115A, a hole transport layer 115B and a luminescent layer 115C, and a cathode 116 laminated in this order on a substrate 111. Although light generated in the luminescent layer 115C may be emitted from the substrate 111, as shown in FIG. 6, the light may be emitted from the cathode 116.
When the light is emitted from the cathode 116, it is often the case that the anode 112 comprises a metal such as chromium (Cr), and the cathode 116 comprises a transparent conductive material such as a compound of indium (In), tin (Sn) and oxygen (O) (ITO; indium tin oxide). The light generated in the luminescent layer 115C may be directly emitted through the cathode 116 as indicated by an arrow 117 in FIG. 6, and as indicated by an arrow 118, the light may be reflected on the anode 112 once and then emitted through the cathode 116.
However, conventionally, the anode 112 comprises chromium or the like, so there is a problem that light absorptance by the anode 112 is high, thereby a loss of light emitted after reflected on the anode 112 is large. The absorptance by the anode has a large influence on the organic electroluminescence device. When light emitting efficiency is low, the amount of current required to obtain the same intensity is increased. An increase in the amount of drive current affects on the life of the device, which is a critical problem in the practical use of the organic electroluminescence device.
In view of the foregoing, it is an object to provide an organic electroluminescence device capable of enhancing the reflectance of the anode so as to improve light-emitting efficiency, and a method of manufacturing the same.